1. Field of the Invention
The present invention relates to a method and apparatus adapted to bunch together a predetermined number of inverted and uninverted PTPs ("press-through packs", as for tablets or the like) being conveyed on a conveying means into a bundle, and to transfer the PTP-bundle to a bucket conveyor which moves intermittently in parallel with a conveying passage, in order to facilitate the binding operation of the bundled-PTPs.
2. Description of the Related Art
Referring to FIG. 1, a generally known PTP 1 has a plastic sheet 2 provided with a plurality of blisters 2a in one surface thereof (hereinafter, referred to as "blistered surface"), tablets 3 or such are put in the blisters 2a, and the blisters 2a containing the tablets 3 are sealed hermetically by a sheet 4, such as an aluminum foil.
A plurality of such PTPs are usually superposed into stacks and bundled with a band or packed into a box or other containers. In order to reduce the thickness of the stacks, one out of two PTPs being conveyed is inverted so that the blistered surface 2 of one PTP faces the blistered surface of the other. Then, the PTPs are slightly shifted so as to prevent abutment of the blisters 2a, as shown in FIG. 2.
The present applicant has previously proposed a method and apparatus for conveying PTPs in U.S. patent application Ser. No. 09/237,144, in order to form the aforesaid PTP stacks automatically. In this application, firstly, a plurality of PTPs aligned parallel with each other are conveyed along a conveying passage with their blistered surfaces facing the same direction. Then, a selected portion of the PTPs being conveyed on the conveying passage are pinched and separated from the remaining PTPS, and the separated PTPs are inverted so that their blistered surfaces oppose the blistered surfaces of the remaining PTPs. Finally, the thus-inverted PTPs are returned onto the same conveying passage and are conveyed together with the uninverted PTPs.
A predetermined number of the inverted and uninverted PTPs have to be subsequently bundled and bound together with a band or other appropriate binding means. However, the aforesaid conveying passage is driven continuously and the PTPs are relatively spaced away from each other, so it is difficult to bundle and take out a predetermined number of PTPs under continuous conveyance.